Red-triangle slugs (Triboniophorus graeffei) are probably the only native slugs that are familiar to Australians. And then only to those who live on the east coast from southern Queensland to central New South Wales.
Triboniophorus is found over a much wider range than that. It's also known from the summit of Mount Bellenden Ker in Far North Queensland and from Mount Kaputar in northern New South Wales. These slugs get around.
The common name comes from the red line that marks the edge of the mantle. (David Nelson's blog has pictures of a slug in all its red-triangled glory.) It's a very variable species. The Bellenden Ker and Kaputar versions are red. (Juveniles from Mt Kaputar have racing stripes.) The Sydney to Brisbane slugs are yellow, apple green or pale pink. All terribly House & Garden.
So what about the little (non-technicolor) white blob in the photo? This is a red-triangle slug from Mt Elliot, just south of Townsville. Triboniophorus is probably found in forest patches all the way up the coast but isn't seen very often. You have to be wandering around at night with a good torch, strong insect repellent and an eye for detail. You also need a shed load of luck.